1. Field of Invention
The invention is directed to sealing devices for isolating an annulus of an oil or gas wellbore and, in particular, to sealing devices having a metal-foam material.
2. Description of Art
Packers for sealing wellbores are known in the art. For example, some packers include swellable materials encased within an expandable sealing element such as a rubber casing or balloon are known in the art. These types of packers expand and, thus, seal to the inner wall surface of a wellbore by contacting hydraulic fluid or other fluid with the swellable materials encased within the rubber casing so that the swellable materials absorb the fluid and expand. In one type of these packers, for example, hydraulic fluid is pumped down a string of tubing having the packer secured thereto. The hydraulic fluid travels down the bore of the string of tubing and through a port that is in fluid communication with an inner cavity of the rubber casing. Swellable materials disposed within the rubber casing are contacted by the hydraulic fluid. As a result, the swellable materials absorb the fluid and expand. As the swellable materials expand and hydraulic fluid is pumped into the rubber casing, the rubber casing expands to seal the wellbore. After expansion, hydraulic fluid pressure is decreased and the rubber casing remains is held in the expanded position solely by the swellable materials having absorbed the fluid.
Other packers are formed of an elastomeric material that is compressed or otherwise forced into the inner wall surface of the wellbore such as by expanding casing or axially compressing the elastomeric material that is disposed along an outer wall surface of the packer assembly.